IZAZOVI U SANACIJI I REKULTIVACIJI DEPONIJA PEPELA I ŠLJAKE IZ TE STANARI

Abstract

As a byproduct of the coal-fired thermal power plants, ash and slag landfills are formed. The potential basic degradation processes related to ash landfills are combined through the occurrence of wind and water erosion, and seepage of waste water. From the planning and design phase of such facilities, it is necessary to properly diagnose the potential causes of degradation, the occurrence of harmful effects, and to plan protection and monitoring for each landfill separately. The constant and binding need for rehabilitation and recultivation of ash and slag landfills, created during the operation of thermal power plants, has become inevitable at all modern thermal power plants. Drainage or seepage water in the contact with the waste, results in the dissolution (leaching) of dangerous elements and compounds from the waste into the seepage water itself. In coal combustion processes, Al, Fe, and Ca, as well as Zn, Ni, and Cd are often released in increased concentrations. Changes in soil quality under the influence of ash can directly or indirectly affect microbiological activity and the root system of plants. The most obvious impact of ash on the soil is reflected in the heavy metals found in the unburned part of the coal. Heavy metals such as B, As, Se, Mo, V, Al and Cd are considered to be extremely dangerous for plants if they accumulate within their habitat. Heavy metals at increased concentrations affect primarily the microbiological cultures present in the soil, which necessarily affects soil properties and overall soil fertility. Ash dumps, in addition to classic mining man-made substrates, in the pedological sense, represent dumps of mineral components formed after various technological activities, which have been greatly altered compared to the original mineral component, including: slag, ash, sludge, brick, mortar, etc. In the process of burning lignite from the Stanari coal basin in the fluidized bed in TPP Stanari boiler, fly ash from the bag filters and ash from the bottom of the CFB boiler's combustion chamber is formed, which is collected after passing through the bed at the bottom of the boiler, and is called solid combustion residues (scr).The location intended for the disposal of waste from TPP Stanari is located at the extreme western part of the internal overburden disposal site within the deposit of the Raškovac field in Stanari coal mine, and covers an area of 55 ha. The planned area secures deposition until the end of operation of the thermal power plant (year 2055). In preparation of individual ash disposal cassettes, an impermeable geomembrane and a protective non-woven geotextile to protect the foil from damage are placed under the ash itself. A waterproof foil (PEHD) is placed on the inside of the slopes of the cassettes and over the geomembrane. Remediation and reclamation of the residue landfill from TPP Stanari has been carried out primarily due to three basic aspects: elimination or minimization of the consequences of water and wind erosion of the deposited material, stabilization of the disposed material, and preparation for potential usage of the reclaimed areas in the future period. The reclamation is designed in two separate time series: a temporary technical and biological phase of reclamation in the first phase and filling individual cassettes, and permanent reclamation of the landfill after disposal of the total amount of waste.